This invention relates to a method of and apparatus for mounting a mirror to a rotatable shaft and more particularly to the technology of mounting a precision mirror to the shaft of a motor or a galvanometer used for laser scanning.
In an optical image projection system with a laser-addressed liquid crystal cell, a laser beam scans the cell illustratively by means of mirrors which are each rotatably mounted to the shaft of a galvanometer as explained, for example, by Heinz and Oehrle ("Rapid Generation of Complex Images with a Liquid Crystal", The Western Electric Engineer, April, 1977). Because of the level of precision and quickness in response required of a mirror used in applications of this type, it is necessary that such a mirror be not only of a high optical quality but also mounted to the rotatable shaft accurately. In other words, the mirror must be mounted centrally so that the centers of mass of the mirror and the mirror mount are and remain on the same axis of rotation as the shaft which provides the rotary motion.
For this purpose, the mounting must be effected so as not to put any unbalanced load on the shaft bearings. Conventional methods by using screw-type clamps are not satisfactory because they tend to loosen with time and usage.